788 



ON THE CHiETOSOMATlD^. 



but the number is difficult to determine (Fig. 25, m.h.). On the 

 dorsal side of the rostrum, the rows of hairs are distinct from, 

 and lie between, the stout 'dorsal hairs,' or seta3, already de- 

 scribed. On the trunk, in each row, there are, alternating fairly 

 regularly with the long hairs, very short, blunt hairs (Fig. 26, i'. A'), 

 which have a similar bulb-like swelling at the base. This, in all 

 the hairs, seems to be hollow. Particles of dirt are frequently 

 found adherin 

 are glandular, and secrete some sort of 



5, to the hairs, and it appears probable that these 



mucilage. 



The 'long 



trunk-hairs' of the dorsal rows are longer than those of the other 

 rows, especially over the region of the genital organs in the 

 female, but the variation in length is not marked. In different 

 specimens, the length varies from 0'025mm. to 0*05 mm., and 

 seems to average about tsvo-thirds the average width of the body. 



In the male, there are, 

 in the region of the anus. 



nuc 



Figs. 28, 28a. 



-Gh 



hasirelli. * 



level of the anus and the beginning 



several hairs differing in 

 character from the ordin- 

 ary trunk-hairs, stronger 

 and stouter, and without 

 the basal swelling. These 

 appear to be very constant 

 in position, i.e., two insert- 

 , ed very close tocjether about 

 half-way between the outer, 

 ventral vow of setae and the 

 anus (Fig. 2 6, ^j)?'. 6'.), two on 

 each side af the anus, one 

 behind, and one in front of 

 it, in the mid-ventral line 

 (Fig.26, a.6'.), and one or 

 two others between the 

 of the tail. The cuticle of 



* Fig.28.— L.S. through body-wall, cutting through one of the meso- 

 dermal bands, and the subcuticular layer on either side of it; (x9o0). 

 Fig. 28a. — T.S. through anterior region of trunk of a young Ch. haswelli; 

 X 950). 



